A blower unit having a centrifugal fan and a scroll casing has been conventionally known. The centrifugal fan includes multiple blades arranged in a circumferential direction of a rotation shaft. The centrifugal fan is provided with a ring part (ring member) having a ring shape defining a center coinciding with an axis of the rotation shaft. The ring part is provided on one axial end of the centrifugal fan, and support the multiple blades. The centrifugal fan is housed in the scroll casing. The scroll casing has an air suction portion defining an air suction opening for introducing air into an inside of the scroll casing on an end with respect to an axial direction of the rotation shaft. Such a blower unit is, for example, described in Japanese Unexamined Patent Application Publication No. 2002-202093, Japanese Patent No. 2940751, and Japanese Patent No. 3351438.
In such a blower unit, the air suction portion of the scroll casing has a bell-mouth wall configured to introduce air from the air suction opening into a radially inner space of the centrifugal fan.
The bell-mouth wall is located on one side of the ring part of the centrifugal fan with respect to the axial direction. In other words, the ring part overlaps the scroll casing, particularly, the air suction portion of the scroll casing in the axial direction. Therefore, it is difficult to reduce the size of the blower unit.